Shelf support



FIG. 1 is a perspective view of a shelf support showing my new design;

FIG. 2 is a top plan view thereof;

FIG. 3 is a side elevational view thereof;

FIG. 4 is a front elevational view thereof;

FIG. 5 is a rear elevational view thereof. 

The ornamental design for a shelf support, substantially as shown and described. 